Highlight Therapeutics: BO-112 meets Phase 2b BCC endpoint

Highlight Therapeutics has reported positive topline results from its Phase 2b SPOTLIGHT-204 trial of BO-112, a double-stranded RNA nanoparticle delivered by intralesional injection, in patients with resectable primary basal cell carcinoma (BCC). The company presented the data as a late-breaking abstract at the European Academy of Dermatology and Venereology (EADV) Congress in Vienna on 30 September 2026.

The trial's modified intention-to-treat population comprised 46 patients with 54 evaluable lesions assessed by a central review committee. BO-112 met the primary composite endpoint of visual and pathological response at week 24, with 61% of patients achieving a Grade 3 or better response across all treated lesions. Notably, 56% of high-risk head and neck patients and 62% of those with facial lesions achieved complete visual and complete pathological response, both graded at the most favourable level.

Trial design and safety profile

SPOTLIGHT-204 enrolled 50 patients in total, including 40 classified as high-risk (36 with head and neck lesions) and 10 as low-risk. Participants received three once-weekly intralesional injections of BO-112 followed by complete surgical excision at week 24. The median patient age was 75 years, and 48% were female.

The safety data were broadly favourable. No serious adverse events and no Grade 3 or above treatment-related adverse events were reported. The vast majority of treatment-related adverse events were mild, with 91% graded as Grade 1; 88% resolved within three days. No treatment discontinuations occurred.

Mercedes Diz, chief executive of Highlight Therapeutics, said the results represent "the first clinical validation of BO-112 in BCC" and give the company "strong conviction to advance into late-stage development." Josep Malvehy, Professor at the University of Barcelona and director of the skin cancer programme at Hospital Clínic of Barcelona, described the results as encouraging and noted that complete responses in more than half of the hardest-to-treat surgical cases is clinically meaningful.

Market context and competitive landscape

BCC is the most common human malignancy globally, and incidence is rising, driven partly by ageing populations and cumulative ultraviolet exposure. Surgery, including Mohs micrographic surgery, remains the standard of care for the majority of patients. While vismodegib and sonidegib, both hedgehog pathway inhibitors, are approved for advanced or locally advanced BCC, options for localised disease that avoid surgery are limited and none are widely adopted for routine dermatology practice.

BO-112's mechanism, activating innate antiviral sensing pathways and inducing immunogenic tumour cell death, positions it within the growing class of intratumoral immunotherapy agents being studied across solid tumours. Several academic groups and smaller biotechs are exploring toll-like receptor agonists, STING agonists, and other innate immune activators for skin cancer, though Highlight Therapeutics claims BO-112 is the first in its class for BCC. That claim has not yet been validated by regulatory review.

For patients with high-risk BCC on the face or neck, where surgery can cause scarring or functional impairment, a well-tolerated non-surgical alternative could address a genuine clinical gap. The company's stated next step is advancing into late-stage development, which will likely require a randomised, controlled design to satisfy European and US regulatory expectations. Engagement with the EMA and FDA on Phase 3 design will be the key near-term milestone to watch.